Computing scale



1967 f s. c. GERLACH 3,352,372

COMPUTING SCALE Filed Dec. 20, 1965 2 Sheets-Sheet 1 :EMEZ' INVENTOR.

Nov. 14, 1967 S. C. GERLACH COMPUTING SCALE 2 Sheets-Sheet 2 Filed Dec. 20, 1965 1* LEE fits-4:

INVENTOR. 57J4A/AEY CL GE-PLACH 'of concrete may be produced that contains 'since the six sacks of cement will be 3,352,372 COMPUTING SCALE Stanley C. Gerlach, 1625 NW. 43rd St., Oklahoma City, Okla. 73118 Filed Dec. 20, 1965, Ser. No. 514,955

8 Claims. (Cl. 177-40) 1 This invention relates generally to improved computing scales. More particularly, but not by way of limitation, this invention relates to an improved computing scale for directly indicating both the unit volume of the material being weighed and the density of the material being weighed.

Most concrete is, at the present time, purchased in the ready mixed form, that is, the concrete as delivered to the contractor on the job site is pro-mixed and includes coarse and fine aggregates, cement, and the proper amount of water to form the desired mixture.

The quantity of concrete ordered is calculated to fill the volume delineated by the concreteforms. For example, assume that a highway fifty-four feet wide is to be paved with a concrete layer one foot deep. The volume of concrete ordered for each foot of highway will be two cubic yards. For each mile of concrete highway laid the necessary concrete volume will be 11,560 cubic yards.

The order is placed for 11,560 cubic yards of concrete containing, for example, six sacks of cement per cubic yard of concrete. Upon receiving the order, the mixing plant mixes a calculated weight (not volume) of coarse aggregate, fine aggregate, cement and water to produce the volume of concrete required. For example, assume I that a single yard of the concrete is to contain 1456 pounds of coarse aggregate, 480 pounds of fine aggregate, 564 pounds of cement (six sacks at 94 pounds per sack) and 250 pounds of water, making a total concrete weight of 2750 pounds per cubic yard.

If the precise density of each of the elements mixed in the concrete is known with a great degree of accuracy, the concrete weight of 2750 pounds should produce a yard of concrete containing exactly 27 cubic feet. However, it has been found in actual practice that the density of the materials, particularly the density of the aggregates, is not known with sufiicient accuracy to insure that 27 cubic feet will be produced for each 2750 pounds 'of material mixed. The discrepancy in density is usually due to the moisture content of the material.

Thus, the aggregate may have a density greater than believed, resulting in a cubic yard of concrete that actually contains less than 27 cubic feet. If the density of the aggregate is less than the assumed value, a cubic yard more than 27 cubic feet.

In the first instance, the contractor purchasing the concrete will have to buy additional concrete to fill the remaining volume of the forms. In the second instance, the concrete ordered will more than fill the volume ordered, but will be most likely of a lower strength than desired distributed over more than 27 cubic feet.

In an'attempt to alleviate the foregoing problem, the

contractor generally spot checks the concrete as it is received from the mixing plant. To spot check the material, he weighs a specified volume of the concrete, usual- 1y less than a cubic foot, multiplies the weight obtained by a factor to convert the scale weight to the weight of .one cubic foot, and then divides the weight of one cubic foot into the calculated weight of a cubic yard. If

the resulting answer equals 27, then the contractor is receiving one cubic yard for each cubic yard ordered. If

the answer deviates either more or less than 27, he is receiving a lower strength concrete but more volume or in United States Patent utilized by unskilled persons.

the alternative, is receiving less volume of higher strength concrete than he has ordered.

Returning to our example, assume that he is receiving only 26 cubic feet per cubic yard ordered, the contractor must then purchase one cubic foot for each yard ordered in order to fill the volume of concrete required. For only one mile of concrete he must order an additional 11,560 cubic feet or approximately 428 cubic yards to complete the job. Manifestly, the contractor cannot remain in business if it is necessary for him to supply the additional money to purchase such a large volume of concrete.

On the other hand, if he receives an additional cubic foot for each yard ordered, the concrete will not conform to the specified strength and he will more than likely have to remove all the concrete previously laid and install the proper strength of concrete at his own expense. In many applications, such as in concrete buildings or bridges, the concrete must be held to specified strength or the building or bridge may fail when loaded.

Many contractors do not have the trained personnel or the time to perform the calculations required to constantly check the actual volume or yield of the pro-mixed concrete to ascertain that it is correct. Also, equipment previously used has been cumbersome and subject to being mislaid or misplaced and is not always available when needed.

Generally, this invention provides a computing scale for indicating the actual unit volume of a preselected unit weight of material, the improved scale includes: a shaft rotatably mounted in the scale, the shaft being rotatable in proportion to the force exerted on the scale by a specified volume of material; a disk connected to and rotatable with the shaft, the disk has a plurality of curvilinear lines thereon generally radiating from the shaft, each of the curvilinear lines indicates an actual unit volume of the material being weighed; and, a plate mounted on the scale overlying the disk and having a center coaxial with the shaft, the plate has a radially extending index thereon and has a plurality of spaced graduations along the index, each of the graduations indicates a prematerial being weighed.

One object of the invention is to provide an improved computing scale that directly indicates the actual unit volume of a preselected unit weight of material being Weighed.

A further object of the invention is to provide an im- A further object of the invention is to provide an improved computing scale that accurately indicates the actual volume in cubic feet of a cubic yard of concrete having a determined weight.

Still another object of the invention is to provide an improved computing scale that requires little or no maintenance during its service life.

An additional object of the invention is to provide an improved computing scale that directly indicates the density of the material being weighed.

One further object of the invention is to provide an improved computing scale that indicates the actual unit volume of a preselected unit weight of the material and simultaneously indicates the density of the material being weighed.

One additional object of the invention is to provide an improved computing scale that can be quickly, easily and economically manufactured.

The foregoing and additional objects and advantages of the invention will become more apparent as the following J) detailed description is read in conjunction with the accompanying drawings wherein like reference characters denote like parts in all views and wherein:

FIG. 1 is a front elevation view of a computing scale constructed in accordance with the invention;

FIG. 2 is a front elevation view of the computing scale constructed in accordance with the invention and having the face removed therefrom to more clearly illustrate the structure of the scale;

FIG. 3 is an enlarged side view, partly in elevation and partly in cross section, illustrating the structure of the computing scale of FIG. 1; and,

FIG. 4 is an enlarged fragmentary view illustrating a portion of the scale faces utilized in the computing scale of FIG. 1.

Referring to the drawing and to FIG. 1 in particular, shown therein and generally designated by the reference character 110 is a computing scale constructed in accordance with the invention. As illustrated, the computing scale 110 includes a weighing scale 112, a container 114 for holding the material to be weighed, a hook 116 for connecting the container 114 to the weighing scale 112, and a cable and hook 118 for supporting the weighing scale 112 and the connected container 114.

As may be seen most clearly in FIG. 3, the weighing scale 112 includes a housing 120 having a shaft 122 rotatably mounted therein, a disk 124 connected to the shaft 122 and a plate 126 overlying the disk 124. The plate 126 is connected by an annular gasket 128 and an annular bracket 130 to the housing 120.

As may be seen most clearly in FIG. 2, the weighing scale 112 also includes a weight supporting member 132 that is movably mounted in the housing 120 and is connected therewith by a pair of springs 134. The springs 134 have one end connected to the housing 120 and the other end connected to the weight supporting member 132.

The shaft 122, which is rotatably mounted in the housing 120 has a pinion gear 136 mounted thereon that is in engagement or mesh with a rack gear 138. The rack gear 138 is movable with the weight supporting member 132 and is movable relative thereto by a threaded screw 140 that is also mounted on the weight supporting member 132.

As can be appreciated from viewing FIG. 2, the threaded adjusting screw 140 is fixed against movement lengthwise on the weight supporting member 132 and is threaded into the lower end of the rack gear 138. Rotation of the screw 140 moves the rack gear 138 relative to the weight supporting member 132, thereby rotating the shaft 132 and pinion gear 136 for reasons that will be more clearly pointed out hereinafter.

As illustrated most clearly in FIGS. 1 and 4, the disk 124 includes a plurality of sets of curvilinear lines designated by the reference characters A, B, C and D. The sets of curvilinear lines A, B, C and D are all similarly formed and generally radiate from the center of the disk 124, that is, from the shaft 122. The numerals 25, 26, 27, 28 and 29 appearing on the lines in each of the sets of curvilinear lines represent the actual unit volume of the material being weighed. That is, each numeral represents a respective volume of 25, 26, 27, 28 or 29 cubic feet. The spacing of the sets of curvilinear lines A, B, C and D is determined so that they will coincide, when the proper weight of material is contained in the container 114, with a respective radially extending index A B C or D The indexes A B C and D are located on the plate 126.

The plate 126, which overlies the disk 124, is preferably constructed from a material that is opaque with the exception of the segments adjacent the indexes A B C and D The area of the plate 126 adjacent the periphery thereof is also made transparent for purposeswhich will appear more fully hereinafter.

Each of the indexes A B C and D is provided with a plurality of spaced graduations. The graduations represent the calculated total weight for one cubic yard of concrete. While only a single index and set of graduations is required, the preferred form of the invention has the graduations extended over the four separate indexes A B C and D to increase the accuracy of the computing scale 110. Manifestly, the exact range of the graduations, that is, the range of calculated weights, can be varied as desired to suit the particular application of the computing scale 110. Also, the precise value of the graduations will be different for different service applications of the computing scale 110.

As is evident in FIGS. 1 and 4, the overlying relationship of the plate 126 and'disk 124 is such that the indexes A B C and D appear to intersect a respective one of the sets of curvilinear lines A, B, C or D. For example, the index A as shown in both FIGS. 1 and 4, appears to intersect the curvilinear lines representing 26,- 27 and 28 cubic feet.

The disk 124 alsoincludes an index F that serves to indicate when the computing scale has been adjusted to a zero or tare weight, that is, to indicate when the computing scale 110 is adjusted to eliminate the effect of the weight of the container 114. The index F also, when the container 114 is filled with material, functions to indicate the density of the material contained in the container 114.

-As clearly illustrated in FIGS. 1 and 4, a density scale 142 is arranged around the circumference of the plate 126 in the transparent area previously mentioned. The density scale 142 includes a plurality of graduations representing the density of the material in the container 114 in conjunction with the position of the index F.

Operation When the computing scale 110 is to be used, the weighing scale 112 is suspended on the cable and hook 118. The empty container 114 isthen suspended from the weighing scale 112 by the hook 116.

The weight of the empty container 114 is sufficient to exert a downward pull on the weight supporting member 132, moving the rack gear 138 downwardly relative to the housing 120. As the rack gear 138 moves downwardly, the pinion 136, the attached shaft 122 and disk 124 rotate in a clockwise direction moving the index F away from a zero index F that is located on the plate 126.

To compensate for the weight of the container 114, the screw is rotated in the proper direction to move the rack gear 138 relative to the weight supporting member 132 and the housing 120. If the index F is to the right of the zero index P with the empty container 114 hanging thereon, the gear 138 is moved upwardly relative to the weight supporting member 132, rotating the pinion 136 and attached shaft 132 in a counterclockwise direction to move the disk 124 until the index F is in alignment with the zero index F The container 114 is then removed from the weighing scale 112 and filled with concrete slurry. The usual method of filling the container 114 is to place sufficient concrete in the container 114 to fill approximately /3 of its total volume. The concrete is then rodded to eliminate the pockets of air that may be trapped when the concrete is poured into the container 114. Additional concrete equal to /3 of the volume of container 114 is then poured into the container 114 and rodded. The container 114 is then completely filled with concrete and rodded for the third time.

The filled container 114 is then suspended from the weighing scale 112 by the hook 116. The weight of the concrete in the container 114 moves the weight supporting member 132 and the attached rack gear 138 downwardly relative to the housing 120. As previously described the downward movement of the rack gear 138 rotates the pinion 136, attached shaft 122 and disk 124, moving the index F in a clockwise direction until the springs 134 terminate the downward movement of the weight supporting member 132. At this time, the indicator F is disposed relatively behind the density scale 142 with the arrow thereon indicating the density in pounds per cubic foot of the material being weighed.

As the disk 124 rotates, the appropriate set of curvilinear lines A, B, C or D is moved to a position directly behind one of the transparent portions of the plate 126, that is, behind one of the indexes A B C or D As previously mentioned, the apparent intersection of one of the curvilinear lines with the graduation for the calculated weight of the material indicates the unit volume of the material being weighed.

Using the same example previously mentioned, that is, using concrete having a calculated weight of 2750 pounds per cubic yard, observe in FIG. 4 that the graduation for 2750 pounds lying 011 the index A apparently intersects the curvilinear line in the set of lines A indicating that the actual unit volume of the material being weighed is 27 cubic feet per cubic yard. Thus, under the assumed conditions, the contractor is actually receiving from the mixing plant one actual cubic yard for each cubic yard ordered. It should also be pointed out that the index F is located behind the density scale 142 indi eating a concrete density of 101.8 pounds per cubic foot.

For the second example, assume that the same weight of material is ordered, that is, concrete having a calculated weight of 2750 pounds per cubic yard. However, assume that the force exerted on the weighing scale 112 by the concrete in the container 114 rotates the disk 124 until the curvilinear line thereon indicating 28 cubic feet per cubic yard intersects the index A at the 2750 pounds graduation. In this example, the actual volume of the material received is 28 cubic feet for each cubic yard ordered, and thus, the contractor is obtaining more volume than requested. The six sacks of cement per cubic yard specified are now distributed in 28 cubic feet rather than in 27 cubic feet. The result is that the concrete has less strength than specified. In this example, the index F is disposed behind the density scale 142 indicating a density of the material of 98.2 pounds per cubic foot. For the third example, assume that the same material is ordered, but that the material in the container 114 exerts sufiicient force on the weighing scale 112 to rotate the disk 124 to the position wherein the curvilinear line of set A indicating 26 cubic feet is located directly behind the graduation for 2750 pounds per cubic yard on the index A Under these circumstances, the actual yield or volume of the material received is 26 cubic feet per cubic yard and, thus, one cubic foot per cubic yard ordered less than the contractor is anticipating. In this situation, the six sacks of cement are distributed in 26 cubic feet of material and will, more than likely, produce a stronger cement than ordered. However, the contractor must now purchase one cubic foot additional for each yard of concrete required to fill the forms. In this example, the index F stops at a position behind the density scale 142 indicating a density of the material being Weighed of 105.8 pounds per cubic foot.

From the foregoing three examples, it can be seen that the contractor has, in the first example, received the precise volume of concrete ordered and that the six sacks of cement specified will be distributed in 27 cubic feet per yard as required. In the second example, he is receiving more concrete than ordered, but the six sacks of cement are now distributed in the increased volume which, as previously pointed out, generally results in a weakened cement that will not meet the specified strength requirements. In the third example, he is receiving less volume of concrete than ordered and the additional volume required to fill the forms must be paid for at his expense. He is receiving a higher quality of cement than ordered in the third example, but he cannot continue in business if he must continually make up the difference in volume at his own expense.

While the foregoing examples relate to a single calbeen described with respect to a culated weight of material falling in the range of the set of curvilinear lines A and the index A it will be understood that the other portions of the computing scale are similarly used if the calculated weight falls within the range of the other indexes B C or D As previously mentioned, a set of curvilinear lines B, C or D is arranged to coincide with a respective index B C or D when the appropriate force is exerted by the material in the container 114, to rotate the disk 124 into the area of the calculated weight per cubic yard shown on the appropriate index B C or D From the foregoing detailed description, it should be apparent that the computing scale 110 provides a means for directly indicating the actual unit volume and density of the material being weighed quickly and easily without requiring calculation on the part of the person weighing the material. Also, while the computing scale 110 has method of indicating the yield of actual volume of concrete, it will be understood that the computing scale may be suitably used for other applications wherein the actual unit volume of the material must be determined from weighing a sample of the material.

It should also be understood that the specific embodiment described herein is presented by way of example only and that mnay modifications and changes can be made thereto without departing from the spirit of the invention or from the scope of the annexed claims.

What I claim is:

1. A computing scale for indicating the actual unit volume of a preselected unit weight of material, said scale including:

a shaft rotatably mounted in said scale, said shaft being rotatable in proportion to the force exerted on said scale by a specified volume of the material;

a disk connected to and rotatable with said shaft, said disk having a plurality of curvilinear lines thereon generally radiating from said shaft, each of said curvilinear lines indicating an actual unit volume of the material being weighed; and,

a plate mounted on said scale overlying said disk and having a center coaxial with said shaft, said plate having a radially extending index thereon and having a plurality of spaced graduations along said index, each of said graduations indicating a preselected unit Weight of the material, one of said graduations, said index, and one of said curvilinear lines being in apparent intersection to indicate the actual unit volume of the material being weighed.

2. The computing scale of claim 1 wherein said disk includes a plurality of similar, spaced sets of curvilinear lines; and,

said plate includes' a radially extending index for each said set of curvilinear lines, and

a set of spaced graduations located on each said index, said sets of graduations each indicating a different range of preselected unit weights of the material.

3. The computing scale of claim 1 and also including:

a second index, said second index being located on said disk; and,

a plurality of radially-spaced graduations located on said plate and adapted to overlie said second index, said radially-spaced graduations indicating the density of the material .being weighed.

4. The computing scale of claim 3 and also including:

a container for said material arranged to be supported by said scale; and,

adjusting means mounted on said scale cooperable with said shaft, to rotate said shaft to compensate for the weight of said container whereby said scale is affected only by the weight of said material.

5. The computing scale of claim 4 wherein said disk includes a plurality of similar, spaced sets of curvilinear lines; and, said, plate includes a radially extending index for each said set of curvilinear lines, and a set of spaced graduations located on each of said index, each of said sets of graduations indicating a different range of preselected unit weights of said material. 6. A computing scale for indicating the actual unit volume of a preselected unit weight of material, said scale comprisingi a housing;

a shaft rotatably mounted in said housing;

a weight supporting member movably located in said housing;

spring means having one end connected with said housing and the other end connected with said weight supporting member;

a pinion gear mounted on said shaft;

a rack gear means slidably located on said weight supporting member and operably engaged with said pinion gear whereby movement of said weight supporting member and rack gear means relative to said housing rotates said shaft in proportion to said movement;

a container for said material arranged to be supported by said weight supporting member;

adjusting means mounted on said Weight supporting member and operably connected with said rack gear means to selectively move said rack gear means relative to said Weight supporting member thereby rotating said shaft to compensate for the weight of said container; 7

a disk connected to and rotatable with said shaft, said disk having a plurality of curvilinear lines thereon generally radiating from said shaft, each of said curvilinear lines indicating an actual unit volume of the material disposed in said container; and,

a plate mounted on said housing overly-ing said disk and having a center coaxial with said shaft, said plate having a radially extending index thereon and a plurality of spaced graduations along said index, each of said graduations indicating a preselected unit weight of the material, one of said graduations, said index, and one of said curvilinear lines being in apparent intersection to indicate the actual unit volume of the material being weighed.

7. The computing scale of claim 6 and also including:

10 a second index, said second index being located on said disk; and,

a plurality of radially-spaced graduations located on said plate and adapted to overlie said second index, said radially spaced graduations indicating the dens- 5 ity of the material being Weighed.

8. The computing scale of claim 7 wherein said disk has a plurality of similar, spaced sets of curvilinear lines; and

said plate includes a radially extending index for each said set of curvilinear lines, and

a set of spaced graduations located on each said radially extending index, said sets of graduations each indicating a difierent range of preselected unit weights of the material. References Cited UNITED STATES PATENTS 514,471 2/1894 Johnson 177-40 539,599 5/1895 SWihaI't 177-40 1,131,126 3/1915 Farrell 177-40 1,435,422 11/1922 Schiske 235-78 XR 2,642,224 6/ 1953 Christiansen 23588 XR 3,086,703 4/1963 Germack 23578 XR FOREIGN PATENTS 1,291,752 3/1'962- France.

757,590 6/1952 Germany. 451,180 8/1949 Italy. ROBERT s. WARD, JR, Primary Examiner. 

1. A COMPUTING SCALE FOR INDICATING THE ACTUATING UNIT VOLUME OF A PRESELECTED UNIT WEIGHT OF MATERIAL, SAID SCALE INCLUDING: A SHAFT ROTATABLY MOUNTED IN SAID SCALE, SAID SHAFT BEING ROTATABLE IN PROPORTION TO THE FORCE EXERTED ON SAID SCALE BY A SPECIFIED VOLUME OF THE MATERIAL; A DISK CONNECTED TO AND ROTATABLE WITH SAID SHAFT, SAID DISK HAVING A PLURALITY OF CURVILINEAR LINES THEREON GENERALLY RADIATING FROM SAID SHAFT, EACH OF SAID CURVILINEAR LINES INDICATING AN ACTUAL UNIT VOLUME OF THE MATERIAL BEING WEIGHED; AND A PLATE MOUNTED ON SAID SCALE OVERLYING SAID DISK AND HAVING A CENTER COAXIAL WITH SAID SHAFT, SAID PLATE HAVING A RADIALLY EXTENDING INDEX THEREON AND HAVING A PLURALITY OF SPACED GRADUATIONS ALONG SAID INDEX, EACH OF SAID GRADUATIONS INDICATING A PRESELECTED UNIT WEIGHT OF THE MATERIAL, ONE OF SAID GRADUATIONS, SAID INDEX, AND ONE OF SAID CURVILINEAR LINES BEING IN APPARENT INTERSECTION TO INDICATE THE ACTUAL UNIT VOLUME OF THE MATERIAL BEING WEIGHED. 